Reports of dreams elicited from different physiologically-identified sleep stages, associations to those dreams, and extensive cognitive and neuropsychological test data will be collected from normal volunteers and from subjects from populations of particular psychiatric (e.g., schizophrenia) and cognitive (e.g., congenital blindness) interest. The dream and association data will be scored using Foulkes' Scoring System for Latent Structure (SSLS), so that we can reliably model the mental processes active in dream formation and compare those processes across different psychophysiological states and different subject populations. We plan to correlate test variables with the dream data in order to determine cognitive and neuropsychological correlates of individual differences in manifest dreams and in the processes by which these dreams are imagined to have been generated. Data from patients with thought disorder will be examined to determine differences and similarities in thought operations presumed to underlie specimens of waking and sleeping thought in normals and in patients. Data from subjects with circumscribed, well-defined cognitive impairments will aid in the isolation of those mental skills which are necessary and/or sufficient for the transformation of memories into dream narratives during REM and other sleep stages.